It is well known that visual animation of screen objects makes a computer-based visual presentation more effective. Adding voice narration to a computer-based visual presentation can further enhance the presentation, especially if the voice is coordinated with animation of the screen objects. Presentation software such as Microsoft® PowerPoint® and Macromedia® Breeze® allow the user to attach and coordinate voice narration from sound files produced by human voice recording. Speech derived from text has advantages over human voice recording for producing voice narration: it is easier to create, update and maintain. The VoxProxy® application uses Microsoft Agent® technology to add cartoon characters with text-based speech to a PowerPoint slide show. The PowerTalk application allows text-based speech to be attached to non-text screen objects on a PowerPoint slide. The PowerTalk application can read the text of text screen objects, such as a bullet paragraph, but cannot add narration over and above what is already written.
Software applications do not exist that can add speech derived from text to a presentation, including: (1) Link speech text to any screen object in a presentation. (2) Enter and edit speech text efficiently, (3) Link multiple voices to screen objects in a general and efficient way, (4) Animate the speech for screen objects that have ordered or interactive visual animations defined for them.